Consolidated Statement of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Income Statement [Abstract]
Revenues (Note 11)	$ 515,033	$ 414,126	$ 390,107
Costs and Operating Expenses:
Cost of revenues	283,999	225,737	209,982
Selling, general, and administrative expenses	160,515	135,753	122,814
Research and development expenses	9,563	7,380	6,677
Restructuring costs and other income (Note 8)	203	(317)	515
Total Costs and Operating Expenses	454,280	368,553	339,988
Operating Income	60,753	45,573	50,119
Interest income	447	269	200
Interest expense	(3,547)	(1,293)	(948)
Income from Continuing Operations Before Provision for Income Taxes	57,653	44,549	49,371
Provision for income taxes (Note 5)	26,070	12,083	14,762
Income from Continuing Operations	31,583	32,466	34,609
Income from discontinued operation (net of income tax provision of $2 in 2016 and $43 in 2015)	0	3	74
Net Income	31,583	32,469	34,683
Net Income Attributable to Noncontrolling Interest	(491)	(392)	(294)
Net Income Attributable to Kadant	31,092	32,077	34,389
Amounts Attributable to Kadant:
Income from Continuing Operations	31,092	32,074	34,315
Income from Discontinued Operation	0	3	74
Net Income Attributable to Kadant	$ 31,092	$ 32,077	$ 34,389
Earnings per Share from Continuing Operations Attributable to Kadant (Note 12)
Basic (in dollars per share)	$ 2.83	$ 2.95	$ 3.16
Diluted (in dollars per share)	2.75	2.88	3.09
Earnings per Share Attributable to Kadant (Note 12)
Basic (in dollars per share)	2.83	2.95	3.16
Diluted (in dollars per share)	$ 2.75	$ 2.88	$ 3.10
Weighted Average Shares (Note 12)
Basic (in shares)	10,991	10,869	10,867
Diluted (in shares)	11,312	11,149	11,094
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.84	$ 0.76	$ 0.68